Pulling a tube and motor lost power

[SkeeterStew]

1997 model ProV 175, compression on all cylinders is great, fuel pumps are new, carbs rebuilt, spark is strong on all 6 cylinders. Marked hub and it's not spun.

I was pulling the kids around on one of those tubes that look like a couch for 3 people the other day and things were going great. Well I made a tight turn to sling them over the wake a little and I lost all thrust. the engine rpm'ed up but I wasn't getting any traction. At least that's what it felt like. So I got off the accelerator and let it rev down but then when i mashed on it again the most I could get was 2500 RPMs and about 10 mph.

We limped home at 10 mph and I checked the carb linkage, timing, idle screws (grabbing at straws) and nothing seemed wrong.

Then get this, I went out to test it a few weeks later and the old sucker ran like new again. I'm bumfuzzled. No reason I could see unless maybe I got water in the unit? I don't think it's possible to get it in the carbs, but maybe I drowned the spark plugs and put it in limp mode or something? I dunno, any ideas would be great.

[Skeeter Jeff]

Spun prop hub.

[SkeeterStew]

Spun prop hub.

Thanks Jeff! I forgot to add that I checked the hub on the second trip out via the mark-the-hub method and it was rock solid after 20 minutes of WOT. I updated the first post.

[Reata210]

Had a 130 Yamaha for 17 years, basically the same engine minus 2 cylinders so very familiar with the engine. Sounds like you have many of your bases covered under the cowl.One item you did not mention which would cause your engine to act as it did is the CDI if failing.I’m leaning away from ignition based on it running fine next time out and more towards fuel starvation.Are all the fuel lines original from tank to bulb and bulb forward?The check valve in the tank sticking could also cause the issue.If it happens again I would remove the check valve or replace it.Could have been as simple as some carbon coming loose and fouling a plug.Needs to happen again to really troubleshoot.I would bring a timing light out and if happens again check each cylinder to see if your dropping one.That would rule out ignition and you can then focus on fuel delivery.

[SkeeterStew]

Had a 130 Yamaha for 17 years, basically the same engine minus 2 cylinders so very familiar with the engine. Sounds like you have many of your bases covered under the cowl.One item you did not mention which would cause your engine to act as it did is the CDI if failing.I’m leaning away from ignition based on it running fine next time out and more towards fuel starvation.Are all the fuel lines original from tank to bulb and bulb forward?The check valve in the tank sticking could also cause the issue.If it happens again I would remove the check valve or replace it.Could have been as simple as some carbon coming loose and fouling a plug.Needs to happen again to really troubleshoot.I would bring a timing light out and if happens again check each cylinder to see if your dropping one.That would rule out ignition and you can then focus on fuel delivery.

I didn't think of anything in the tank. Where is the check valve exactly? I have an elbow at the top of the tank, then about 6" of hose, a bulb, and then a hose running to the (clean) fuel filter on the engine.

[Reata210]

I didn't think of anything in the tank. Where is the check valve exactly? I have an elbow at the top of the tank, then about 6" of hose, a bulb, and then a hose running to the (clean) fuel filter on the engine.

Many check valve/anti siphon valves thread into the tank at the bottom and there is a barbed fitting for the fuel line that runs to the bulb. Can also be at the top with a section of line that runs to the bottom of the tank.Valve can be part of the pickup in the threaded section or in the bottom connected to the line that sits in fuel.This sounds like what you have.The elbow you mentioned is likely the check valve.

[Reata210]

This is most likely what you have. The check valve threads into the top.

http://www.boatersplus.com/moeller-24-fuel-pick-up-with-npt-aluminum-fitting.html

[SkeeterStew]

This is most likely what you have. The check valve threads into the top.

http://www.boatersplus.com/moeller-24-fuel-pick-up-with-npt-aluminum-fitting.html

That's exactly what I have! Thanks! I'll remove that little sucker before I go out next time and see if it's causing the trouble.

[SkeeterStew]

Just a little update here. I was out on it yesterday trying out some things and figured out the problem. It's the blasted electrical gremlins! I've got a short somewhere in my wiring to the motor. I found it by taking a turn at a whole 10 mph and i noticed the gas gauge bottomed out when I turned right. When i turned back left it popped back up. So I turned it left and nailed it - the power was back!
Now i've got to dig in there and figure out where it's messed up. I wiggled the black rigging hose going to the motor and could get it to repeat so into the rigging I go.

[Charlie206]

The battery cables themselves are known to go out over time. Of course, anything in the main engine harness could be the cause but I would manipulate while metering the batt cables first.

[Reata210]

Glad to hear you narrowed it down to just a couple wires

[SkeeterStew]

I thought about re-titling this thread "Don't complain when God closes a door, he's likely to throw you out a window" HAHA!

I opened up my black rigging tube with the short in it. Inside I found.....



THIS!













As you can see, my fuel line wore through the outside casing and leaked oil and gas all over my wires, messing up their insulation and making things very goopy. There's actually bits of casing and oil on every single wire in the group there. It's like someone peeled a hotdog. I'm assuming this also caused my engine to suck up air and run slower than it should at higher speeds. That combined with my prop having one fin that is shorter than the other 2 (unless that's normal) should explain my top speed loss.


This one wire that goes to (I think) the trim was broken clean in two. It's orange. The blue one coupled with it was broken half in two.











I connected the wires back together and used dielectric grease and heat shrink-wrap on them to keep them dry and happy. I already have fuel hose so I'll replace that and then wrap it all back up & see what's what.

Another electrical gremlin I found was in the key switch. i have to push the key a little past "On" or it doesn't act like it's on. I'll open that up later and fiddle with it. For now it'll be ok now that I know the trick. I've got a fishing trip this weekend and Ol' Nemo's gotta be ready by then!

Thanks for the help and encouragement guys, as always! Love this site.

[Reata210]

Glad to hear you located your problem. Let us know how it runs once back on the lake.